The need frequently arises when handling fluids to connect one conduit with another. When the installation is such that repeated connections and disconnections are required, it is desirable to utilize a coupling device that can be quickly joined and disconnected. A number of couplings or connectors have been devised over the years to meet this need, and such are commonly called quick connect-disconnect couplings.
While there are several designs for quick connect-disconnect couplings, the type to which this invention relates will typically include a male element having a nose portion that is receivable within the socket of a female element, the outer ends of the two elements being equipped with means to connect them with fluid conduits. One of the elements, typcially the female element, will carry releasable detent means, adapted to engage with groove means on the other element when the two are interengaged. A slidable sleeve will be mounted on the element carrying the detent means, and is movable between a locking position in which it locks the detent means in engagement with the groove means, and a retracted position in which disengagement of the two coupling elements can occur. Typically, the detent means will consist of an annular array of balls mounted in a race, and the sleeve will be biased toward its locking position by a spring. Movement of the sleeve toward the locking position will usually be arrested by a simple snap ring or the like, which is engaged by a shoulder on the sleeve.
When the fluid pressures involved are relatively low, the wear factors affecting a quick connect-disconnect coupling of the type just described are minor, and a long period of trouble-free use is commonly obtained from the coupling. However, it has been found that when operating fluid pressures are high, perhaps in the 2,000 to 3,000 psi range, the typical commercially available quick connect-disconnect coupling can become subject to wear over a relatively short time that will affect its performance, and which can result in accidental disconnecting. When this occurs during handling of a high-pressure fluid, the result can be quite damaging. This is particularly true if the fluid involved is a hazardous material, such as natural gas or the like.
One use for quick connect-disconnect couplings is in equipment utilized to transport natural gas under high pressures in pressure vessels, a method and system for accomplishing this having been first advanced in U.S. Pat. No. 4,139,019. In that patent quick connect-disconnect couplings are utilized to connect a loading conduit with a vehicle-mounted pressure vessel means, the latter having a loading manifold provided with one element of such a coupling. The other coupling element is mounted on the end of the loading cohduit. The quick connect-disconnect coupling in the patent must be made up each time a new pressure vessel means is connected to receive natural gas, and the pressures involved will be in the 2,000 to 3,000 psi range.
If the quick connect-disconnect coupling employed in practicing the invention of the cited patent should accidentally fail while under high pressure, a serious situation could result. First of all, separation of the coupling elements could result in one of the elements being propelled at high velocity into equipment or persons situated nearby, causing damage or injury. Secondly, if the failure of the coupling allows natural gas to escape, the possibility of a fire or an explosion would exist. Obviously, accidental separation of the coupling elements should be avoided, if at all possible.
It has been found that accidental uncouplings can occur if the workman does not properly engage the male and female elements, or if the sleeve controlling the detent means is not fully moved into its locking position. Further, it has also been found that under high-pressure conditions and repeated usage, the detent means and components associated therewith tend to wear more quickly than usual. This wear, while often being relatively minor, can nevertheless be sufficient to allow the sleeve to move axially in either direction, resulting in an uncoupling action.
There is need for a safety arrangement for utilization with such quick connect-disconnect couplings, one that will assure that the coupling components are in proper interengaged relationship before high-pressure fluid is applied to the conduits, which will maintain the coupling components in proper relationship during fluid flow, and which will prevent damage should the coupling fail. The present invention is intended to satisfy this need.